1. Field of the Invention
The application field of the present invention relates generally to the improvements of electric motorcycles.
In particular, the invention relates to a preferred embodiment of an electric motorcycle model provided with particular structural features which make said motorcycles maintenance easier and more efficient.
2. Brief Description of the Prior Art
Generally, the supply of electric vehicles has recently remarkably increased mostly caused by the increasing cost of internal combustion engines fuel, and above all, by the will of reducing the emission of carbon dioxide and other pollutants produced by the internal combustion engines, which represent a serious cause of air pollution, a phenomenon, that everyone wants to be rapidly resolved.
Therefore, the evolution of supply of traditional vehicles towards electric vehicles should be a trend destined to strengthen, although there are still many difficulties which impede its development.
In particular, the more important technical problems are here summarized:                the development and deployment of more efficient and economic energy storage technologies,        the charge management systems of said systems,        the electronic controls needed for an effective vehicle functioning and                    the general supply and maintenance processes.            Concerning the other technical components needed for manufacturing electric vehicles, there seems not to be particular problems. In fact, regarding the electric motors, it is possible to rely on very mature technologies able to work in operative conditions required by the transportation sector. While considering the low power mechanic and electric need by electric vehicles, it is possible to adapt the huge state of the art developed for the traditional vehicles without particular difficulties.            What is generally stated for the electric vehicles, it can also apply to the electric motorcycles; but, in this case, there is another problem due to many space limitations.            In fact, for traditional motorcycles, the fuel tank can have various shapes and can be almost mounted in any position. The motor as well can be positioned almost anywhere since the transmission occurs through a chain (or other transmission mechanisms) which can transmit the motion to the driving wheel at various distances.            Generally, it can be stated that in the traditional motorcycles, the key systems for the motorcycle operations are positioned in a distributed way over the entire motorcycle, and the limits are mainly due to aesthetic or maneuverability reasons.            Another prerogative of the traditional motorcycles is that the expertise needed for the maintenance of these kinds of motorcycles is very diffused. In fact, it is very easy to find a motor mechanic able to understand the cause of possible malfunctioning and to carry out the main maintenance operations of a traditional fuel supplied motorcycle. Therefore, the electric motorcycles are characterized by some important differences with respect to the traditional supplied motorcycles.            Obviously, the electrically operated motorcycles do not need a tank for the fuel, and the energy needed for the locomotion is obtained by batteries which are much bulkier than the batteries provided for traditional motorcycles because these batteries need to support low consumption functions. Moreover, for technical reasons, such batteries cannot be shaped as gasoline tanks. For economic reasons as well, the battery (or batteries) shape represents a limitation to the motorcycle design conception.            In addition to the battery shape, which is generally a parallelepiped box, another design limit is also the fact that the battery is to be suitably protected and isolated, both for protecting it against possible damage and for protecting the motorcycle user against possible accidents. Also, the electronic subsystems of electrical motorcycles are much more complex since, in addition to the electric loads provided for the traditional motorcycles, the electronic subsystem is needed to manage power loads associated to the electric motorcycle operation.            These electronic subsystems are designed also to control the battery charge steps. In general, the more precise is the control of the batteries charge and discharge, the greater is the number of charging/discharging cycles that a chemical battery can do with acceptable performance and yield. To increase the motorcycle autonomy, more batteries are available that have possible different degrees of wear and charge states, causing the function of the battery control to be yet more delicate and critical. For these reasons, the electric motorcycles are provided with a subsystem, called BMS (Battery Management System), which is carried out by a microprocessor board which supervises these functions. The BMS is a quite critical element, from the reliability point of vue, since it is provided with both a pure computational electronics and power electronics since it needs to manage the relatively high energies stored inside the accumulation systems (or batteries).            Moreover, in addition to the traditional electronic control unit needed for controlling the electric power typical of a vehicle (for example for lighting), there is a need of a power control unit (which is generally distinct from the traditional electric control unit) for controlling the electric energy provided to the motor (for example for accelerating) or for managing the energy recovery during decelerations.            Also, the power control unit is a very stressed subsystem which can be subjected to failures and malfunctioning.            These considerations about the electronics for electric motorcycles are aimed to confirm that the electronics of an electric motorcycle are more complex than the very simpler one of a traditional motorcycle.            As a consequence, nearly all failures or malfunctioning of electric motorcycles are caused by batteries deterioration or to a malfunctioning of the electric and electronic subsystems needed for the functioning of an electric motorcycle: in particular the BMS subsystem and the power control unit.            Because of the complexity of the onboard electronics of an electric motorcycle, it is even more complex in case of failure or malfunctioning to be diagnosed than with a traditional motorcycle as well, and basically, a complete and precise maintenance service can only occur at specialized computerized work stations for carrying out diagnostic tests, and these work stations can be available only in specialized sites dedicated to these functions; and, of course, these sites cannot be diffusely distributed as well as the traditional ones.            Generally, yet as a consequence of what previously stated, in most cases, the failures occurring to electric motorcycles are resolved by substituting a failing component.            As previously stated, the needed expertise for maintenance and repair of electric motorcycles is not so diffused as the one for maintenance and repair of traditional motorcycles, and, given the technical peculiarities associated to electric motorcycles, it is expected that the maintenance network of such means is articulated on two levels, wherein the most precise diagnostics is carried out at a strongly centralized level (concentrated in few or very few sites).            Many electric motorcycles available on the market are the evolution of traditional motorcycles, and the criteria used for providing the frames are possibly derived by the various frame kinds yet available in the mature field of traditional motorcycles.            Therefore, the current electric motorcycle is provided in diffused models in which, after adopting a kind of frame inspired by traditional shapes, technical attempts have been made to mount the battery (or batteries) and the various electronic components inside available spaces: so, the batteries are generally arranged inside the greater and more protected space among the available ones, while the various electronic components, smaller and often with less shape limits, are arranged in distributed way in the more suitable spaces according to the various models.            The electric motorcycles currently have on the have their operating elements arranged in different positions and are provided with different access points for their removal.            Another prerogative of the electric motorcycles is that electric motors can be more compact than the internal combustion ones, and that they can also be directly integrated with the driving wheel, thus avoiding the need of a transmission system for transmitting the motion from the motor to the wheel, since the rotary motion is generated on the same wheel.            It is to be said that the electric motor technology is particularly mature and reliable, and therefore the motor failures are to be considered a very rare (almost minor) event with respect to the failures the other electric and electronic subsystems can be subjected to.            The possibility to integrate the motor directly in the driving wheel, as said, eliminates the need of a transmission system and, as a consequence, eliminates the limit (like in the internal combustion engine motorcycles which need a transmission system, for example a chain) to preserve a free space between the motor and the driving wheel, thus eliminating portions in movement subjected to wear and in need of lubrication, as one of the causes for which maintenance is required in the traditional motorcycles.            Still concerning the evolution trend of electric motorcycles it is observed how, in many models, attempts were made to provide motorcycles in which the battery removal is simplified, and doable by their users.            This trend is justified by the fact that the charge times for a battery are not comparable to the fuelling times of a traditional motorcycle, the battery recharge times being very much longer.            It was then considered that the replacement of an exhausted battery with a charged one could be an alternative solution to recharging time in order to speed up the procedure comparably in time to fuelling.            Generally, the possibility to extract the battery allows providing more flexible supply procedures: for example if the motorcycle is parked in a place not prepared for recharging, the motorcycle user can extract the battery and bring it to a place where it is possible to recharge it. Regardless of the effective application of these procedures, all most recent models of electric motorcycles are have one or more batteries housed in spaces accessible by their users as well, who, at least theoretically, should be able to remove the so called “battery pack”.            This structural feature of the most recent electric motorcycles seems not to be really useful since there are not so many users of electric motorcycles, who after parking their vehicle, remove the “battery pack” in order to substitute it or bring it to a suitable place for recharging. The little success of these procedures can be justified by the fact that there are not yet diffused standards allowing an efficient battery substitution and recharging in suitable service stations.            However, it is also possible that the removal operation of a “battery pack”, which is generally very heavy, is an extremely uncomfortable operation for the user. Moreover, the more the “battery pack” light is, the smaller the autonomy is that said batteries can ensure, and so the maneuverability of the battery is a balancing point against the battery's autonomy, which is certainly more important.            Generally, the user needs an ever greater autonomy, and this leads to bulkier and heavier batteries, ever less suitable to be regularly handled by the same user.            Considering the limits of autonomy which can be reached by electric motorcycles, and their battery volumes and weights, it is obvious to aim at providing means for providing a typical daily usage (commuting to work journeys or similar), with a sufficient autonomy. In this kind of usage, it would be desirable recharging the batteries in a service station, without the need to remove the battery.            In this case, which can be considered as a reference to define structural and performance goals, it seems that the easiness to remove the battery pack by the user is not a particularly important aspect. Another typical case of usage is the one of electric motorcycle fleets, which can be used for urban services (for example mail delivery services). Also in these cases, the motorcycles are subjected to a daily typical regular usage which comprises also long stop times; therefore also in this case, the main requirement is not represented by the maneuverability of the battery, but consists in the possibility to ensure an autonomy able to cover the typical need of a work shift. All these considerations about the electric motorcycle features, according to the known art, allow to address a technical problem still felt in many electric motorcycle usages: it is a question of ensuring an efficient maintenance of such means while considering that a network of service stations suitable for said maintenance cannot be capillary, and that the times and repair costs need to be the lowest possible.                        